JabRef 3.8.1
linux 4.8.15-300.fc25.x86_64 amd64
Java 1.8.0_51

Steps to reproduce:

1. Add any arXiv preprint, e.g. 1604.06709
2. Click on Quality -> Look up full text documents
3. The online link is still listed primary, so when clicking on the sheet icon in the bibliography list, you get redirected to https://arxiv.org/pdf/1604.06709v1.pdf, although a local PDF is present.

In my view this behavior is incorrect. Once the full text document has been fetched, it should become primary, not the online link. Currently I have to change ordering by hand for every new entry, which is a lot of extra work.